Researchers at Clarkson University and the State University of New York at Plattsburgh have published the first study showing that children with autism spectrum disorder have differences in protein levels in their saliva when compared to typically developing children. The study appeared in the journal Autism Research.

Autism spectrum disorder currently affects one in 68 US children, and the number of people diagnosed with autism continues to rise. Diagnosis is currently made based on behavioral observations, but no biological test for autism exists. A biological test could aid in earlier diagnosis, helping to direct people with autism to interventions.

The scientists, led by PhD student Armand Ngounou Wetie, studied saliva from six children diagnosed with autism, age 6-16, compared to six typically developing children in the same age range. They used a technique known as mass spectrometry to measure protein differences in saliva taken from the two groups.

According Dr. Alisa Woods, one of the researchers leading the study: "we found nine proteins that were significantly elevated in the saliva of the people with autism and three that were lower or even absent. This is the first study to identify these changes in saliva, which is a relatively easy biofluid to obtain for clinical use or research."

The proteins identified primarily have functions in immune system responses, or are elevated in people with gastrointestinal problems. The group also reported that several of the identified proteins interact with one another.

Dr. Costel Darie, a co-lead author and proteomics expert noted "We are the first in the world who proposed a protein complex as a potential biomarker signature, which gives us information not only about the proteins, their relative quantities and their modifications, but also about their interactions with other proteins."

The work is promising for the eventual development of an autism diagnostic test although more subjects need to be studied to confirm that the markers are consistently different in people with autism.

Ngounou Weitie added "We have found some interesting proteins that are different from children with autism compared with controls, and I think the next stage would be to increase the pool of samples to confirm those findings."

The group plans to further study these protein differences in larger groups of children with autism, and also in specific subtypes of autism.